// Vertex shader

struct VertexInput {
    @location(0) position: vec3<f32>,
    @location(1) fg: vec4<f32>,
    @location(2) bg: vec4<f32>,
    @location(3) tex_coords: vec2<f32>,
};

struct VertexOutput{
    @builtin(position) clip_position: vec4<f32>,
    @location(0) fg: vec4<f32>,
    @location(1) bg: vec4<f32>,
    @location(2) tex_coords: vec2<f32>,
};

@vertex
fn vs_main(
    model: VertexInput,
) -> VertexOutput {
    var out: VertexOutput;
    out.fg = model.fg;
    out.bg = model.bg;
    out.tex_coords = model.tex_coords;
    out.clip_position = vec4<f32>(model.position, 1.0);
    return out;
}

// Fragment shader

@group(0)
@binding(0)
var t_font: texture_2d<f32>;
@group(0)
@binding(1)
var s_font: sampler;

@fragment
fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
    let original : vec4<f32> = textureSample(t_font, s_font, in.tex_coords);
    if (original.r < 0.01 && original.g < 0.01 && original.b < 0.01) {
        discard;
    }
    if ((original.r > 0.1 || original.g > 0.1 || original.b > 0.1) || original.a > 0.1) {
        return original * in.fg;
    } else {
        return in.bg;
    }
}
